Just a warning, the AO and AOE are ourgrown by height before most kids are ready for a booster. The top notch CANNOT be used for the 5 point harness, it is only to use to position the headrest in booster mode. It is not reinforced. Most kids outgrow the 5 point harness by 3 years old, which is too young for a booster. This is not the last seat anyone will ever need! They also do not make great boosters. The best thing I can say about them is they rear face to 35lbs. They are definately not worth the money, IMO, when you will just have to buy another seat anyway!

Personally, I'd go with a Safety 1st Uptown or Fisher Price Safe Voyage Deluxe (FPSVD) before I'd ever buy an AOE. The FPSVD was made by Britax for Fisher Price and is sort of a bargain version of the Marathon. It harnesses to 55 lbs instead of 65 lbs like the Marathon does and it can't be tethered RF (but neither can an AOE or Uptown), and it's on sale for $129 right now at Albeebaby!

You should stop by the boards at www.car-seat.org and ask for seat recommendations! I'm a frequent poster there, too!